From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753348AbaLGSzi (ORCPT ); Sun, 7 Dec 2014 13:55:38 -0500 Received: from mail-wg0-f45.google.com ([74.125.82.45]:37464 "EHLO mail-wg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753005AbaLGSzh (ORCPT ); Sun, 7 Dec 2014 13:55:37 -0500 Date: Sun, 7 Dec 2014 19:55:33 +0100 From: Michal Hocko To: Tejun Heo Cc: linux-mm@kvack.org, Andrew Morton , "\\\"Rafael J. Wysocki\\\"" , David Rientjes , Johannes Weiner , Oleg Nesterov , Cong Wang , LKML , linux-pm@vger.kernel.org Subject: Re: [PATCH -v2 2/5] OOM: thaw the OOM victim if it is frozen Message-ID: <20141207185533.GA29065@dhcp22.suse.cz> References: <20141110163055.GC18373@dhcp22.suse.cz> <1417797707-31699-1-git-send-email-mhocko@suse.cz> <1417797707-31699-3-git-send-email-mhocko@suse.cz> <20141206130657.GC18711@htj.dyndns.org> <20141207102430.GF15892@dhcp22.suse.cz> <20141207104539.GK15892@dhcp22.suse.cz> <20141207135940.GB19034@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141207135940.GB19034@htj.dyndns.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 07-12-14 08:59:40, Tejun Heo wrote: > On Sun, Dec 07, 2014 at 11:45:39AM +0100, Michal Hocko wrote: > .... > > void mark_tsk_oom_victim(struct task_struct *tsk) > > { > > set_tsk_thread_flag(tsk, TIF_MEMDIE); > > + __thaw_task(tsk); > > Yeah, this is a lot better. Maybe we can add a comment at least > pointing readers to where to look at to understand what's going on? > This stems from the fact that OOM killer which essentially is a memory > reclaim operation overrides freezing. It'd be nice if that is > documented somehow. diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 19a08f3f00ba..fca456fe855a 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -426,6 +426,13 @@ void note_oom_kill(void) void mark_tsk_oom_victim(struct task_struct *tsk) { set_tsk_thread_flag(tsk, TIF_MEMDIE); + + /* + * Make sure that the task is woken up from uninterruptible sleep + * if it is frozen because OOM killer wouldn't be able to free + * any memory and livelock. freezing_slow_path will tell the freezer + * that TIF_MEMDIE tasks should be ignored. + */ __thaw_task(tsk); } Better? -- Michal Hocko SUSE Labs